I'm developing a game for Android and I will need a server to handle the multiplayer side but I don't know which option choose. The game is a simple culture game with answers and replies, like 'who wants to be a millionaire' for example, but with 3 users playing agains each other. This is the main concept and now I need to help choosing the method to make this. I will need the server group the users in sets of 3 and handle the response of users and tell to the others if the other user guess the right answer. I think you understand the idea.

I think in NodeJS ... but I don't know if is possible to do this or I have other better options.

Nodejs would probably do fine for this kind of game. Look at socket.io as a transport mechanism.

Note that your server architecture (the structure of the code and how servers share state) will *drastically* have to change once you get past the point where a single nodejs process can serve all your users. But that's probably beyond the tens of thousands of users point, so you'll have some time to think about what to do when you get there :-)